Thursday, February 25, 2010

Human pheromones - androstenol activates hypothalamus in women.

There is continuing debate over whether, and to what extent, we humans (like other mammals) might use body odors secreted from our skin in signaling sexual attraction, aggression, submission, etc.  Several progesterone derivatives have been shown to activate regions of the thalamus and hypothalamus, and the activations are differentiated with respect to sex and sexual orientation of the smeller in relation to the respective compounds.   Slavic et al. asked whether compounds actually released by our bodies have pheromone properties, and focused on highly volatile androstenol, which is found (primarily in males), in sweat, urine, plasma and saliva. They found that smelling androstenol (unlike several common odors) causes activation of a portion of the hypothalamus in women that animal data suggests mediates pheromone triggered mating behavior. (The article is open access, and you can see the brain imaging data there.)

5 comments:

Anonymous said...

Some scientists tend to confuse co-existence with cause and effect. It is important to know the difference when discussing brain activation. The article you mention, along with two other articles helps to illustrate the difference.

Savic, I. and H. Berglund (2010) provides information about a pathway that connects olfactory/pheromonal input (i.e., androstenol) to hormonal changes in the brain. This is an example of cause and effect.

The evolved neurophysiological mechanism that allows olfactory/pheromonal input from the social environment of all mammals to cause changes in behavior is detailed in an award-winning journal article that was concurrently published as a book chapter. See: The Mind’s Eyes: Human Pheromones, Neuroscience, and Male Sexual Preferences.

An example of co-existence is found below. If there is a mechanism that allows visual input from the human social environment to cause changes in behavior, the mechanism is not known to known to exist in other mammals, or in any species.

Platek, S. M. and D. Singh (2010). “Optimal Waist-to-Hip Ratios in Women Activate Neural Reward Centers in Men.” PLoS ONE 5(2): e9042. An unknown mechanism might – if it exists — link visual input to brain activation. If brain activation occurs via this unknown mechanism, it might be associated with the development of men’s preferences for the visual appeal of a woman’s waist-to-hip ratio (WHR).

The visual link to brain activation associated with WHR preferences is not required for the development of this preference as shown in the following research.

Karremans, J. C., E. F. Willem, Willem E., et al. (2010). “Blind men prefer a low waist-to-hip ratio.” Evolution and Human Behavior (in press).

If men who are born blind develop what was believed to be a visual preference for low WHR's, it's reasonably to say that this preference is not based on visual input. Preferences for sexually dimorphic signals of reproductive fitness of other mammals develop through conditioned responses to olfactory/pheromonal input. The research cited above strongly suggests that we are not much different from other mammals--except for the fact that we "think" we are not like them.

human pheromones said...

Nice post! I enjoyed reading this informative post. This is very useful. Wish I stumbled your site before. Thanks a lot for this valuable information.

-nickolei-

pheromones said...

Wow. This was very informative and well written. Great information here!

pheromones said...

I have found that the brain reaction are certainly different when a woman is exposed to pheromones in her life. They actually do react in ways that are quite interesting to men. Androstenol does have great capabilities to deliver certain reactions. Thanks for a great read!

Clay Williams said...

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